Mortality from cancer and chronic respiratory diseases among workers who manufacture carbon electrodes

Objectives-To investigate the risk of cancer and non-neoplastic respiratory diseases among workers who manufacture carbon electrodes, as this industry entails exposure to mixtures of polycyclic aromatic hydrocarbons. Methods-A historical cohort study was carried out of 1006 male workers empl oy ed for at least 1 year between 1945 and 1971 in a carbon (graphite) elec trode production plant in central Italy, who were followed up for mortality between 1955 and 1996. The ratio of observed to expected deaths (standardi sed mortality ratios, SMRs) was computed from both national and (for the pe riod 1964-96) regional age and period specific mortalities. A multivariate Poisson regression analysis was performed to investigate the relative risk (RR) of death according to duration of employment and time since first empl oyment in the factory. Results-A total of 424 workers had died, 538 were still alive, and 44 were lost to follow up, Mortalities from all causes, all cancers, and respirator y tract cancer were in Line with the regional figure. An excess was found o ver the expected deaths from skin cancer including melanoma (SMR 3.16, 95% confidence interval (95% CI) 0.65 to 9.23) and from non-neoplastic respirat ory diseases (SMR 1.58, 95% CI 1.16 to 2.11). Poisson regression analysis i ncluding age as a covariate showed an increased risk of dying from gastric cancer with increasing duration of employment, and an increase in the RR of dying from lung cancer and from nonneoplastic respiratory diseases with in creasing time since first employment, although the linear trend was not sig nificant. Conclusion-This study supports previous findings that working in the carbon electrode manufacturing industry may not increase the risk of dying from r espiratory cancer. However, a possible association with non-malignant respi ratory diseases cannot be excluded.